Nattiya Kanhabua , Tu Ngoc Nguyen and Claudia Niedere L3S Research - - PowerPoint PPT Presentation

“Concise Preservation by Combining Managed Forgetting and Contextualized Remembering”

EU/FP7 ForgetIT Project (2013-2016) http://www.forgetit-project.eu

What Triggers Human Remembering of Events?

Large-Scale Analysis of Collective Memory in Wikipedia

Nattiya Kanhabua, Tu Ngoc Nguyen and Claudia Niederée

L3S Research Center , Hannover, Germany

Motivation: ForgetIT Project Human Forgetting and Remembering Collective Memory in Wikipedia Experiments and Discussion Conclusions

Outline

However, we are facing:

• Dramatic increase in content creation (e.g. digital photos)
• Increasing use of mobile devices with restricted capacity
• Information overload and changing professional and private lives
• Inadvertent forgetting due to lack of systematic preservation

Forgetting plays a crucial role for human remembering and life (focus on current, relevant information; ignore redundant details) Managed forgetting ≠ automatic deletion Instead: a range of forgetting options e.g.

• Resource condensation
• Change of indexing & ranking
• Reduction of redundancy

A computer that forgets intentionally ? And, in context of digital preservation??

However, we are facing:

• Dramatic increase in content creation (e.g. digital photos)
• Increasing use of mobile devices with restricted capacity
• Information overload and changing professional and private lives
• Inadvertent forgetting due to lack of systematic preservation

Forgetting plays a crucial role for human remembering and life (focus on current, relevant information; ignore redundant details) Managed forgetting ≠ automatic deletion Instead: a range of forgetting options e.g.

• Resource condensation
• Change of indexing & ranking
• Reduction of redundancy

A computer that forgets intentionally ? And, in context of digital preservation?? Managed forgetting = to remember the right information

Individual memories are subject to a fast forgetting process [Ebbinghaus, 1885]

• Rapidly forget details -> “less redundancy”

Episodic memory (of one’s past event) is reconstructed from similar events/context

• Rely on common patterns -> “false memory”

Memory bumps in the forgetting curve is caused by reminding or triggering of:

• A physical object (e.g. a printed photo)
• A digital memory system
• Different subsequent events

Human Forgetting and Remembering

• H. Ebbinghaus, Über das Gedächtnis. Untersuchungen zur experimentellen Psychologie. Duncker & Humblot,

Leipzig, 1885.

• E. Tulving, Episodic memory: From mind to brain. Annual review of psychology, vol. 53, no. 1, pp. 1-25, 2002.

“ Collective memory is a socially constructed, common image (memory)

• f the past of a community, which frames its current understanding

and actions.” [Halbwachs, 1950]

• Crowd phenomenon and important to societal processes
• Not static as determined by the concerns of the present

From Individual Memories to Collective Memory

• M. Halbwachs, On collective memory. Chicago: The University of Chicago Press, 1950 (Translation).

Flashbulb memories in cognitive psychology

• A study of remembering of high-impact events, e.g.,

The British Royal Wedding or September 11 attacks

• Aspects: details, confidence, consistency of memory
• ver time, impact of media coverage
• Qualitative study: limited number of events and users

Collective Memory in Wikipedia

Wikipedia as a source for global memory

• Largest and most up-to-date online encyclopedia

(19M registered users, 30K active editors)

• Social negotiation and construction reflected in

early editing activities and talk pages

• Indicators for identifying real-world events
• C. Pentzold, The online encyclopaedia wikipedia as a global memory place, Memory Studies, 2009.
• M. Georgescu, N. Kanhabua, D. Krause, W. Nejdl, and S. Siersdorfer, Extracting event-related information

from article updates in wikipedia, ECIR'2013.

View logs as the signal for collective memory

• Public page view traffics with a long time span
• Not directly reflect how people forget; significant

patterns are a good estimate public remembering

• Large-scale analysis complements (1) qualitative

studies (2) analyzing article content (scalability)

Contributions

First study of identifying catalysts for event memory triggering by using time series analysis techniques:

• temporal correlations in peaking page visits between events,
• a surprise score or the residual sum of squares on prediction error, and
• the skewness of view shapes as a catalyst for memories

Identify the relationship between events by using different features

• the role of time passed, the same types of events, the size or magnitude of

events, the near-by city or neighbor country

Analyze over 5500 high-impact events from 11 event categories Related to the previous study by [Au Yeung and Jatowt, 2011]

• Analyzed references to the past (as an indicator to what is remembered) in a

large news collection for identifying, which years are most frequently referenced

C.-m. Au Yeung and A. Jatowt, Studying how the past is remembered: Towards computational history through large scale text mining, CIKM’2011

We propose a 3-step approach, for a given event:

• 1. Compute “remembering scores” of past events within the same category
• 2. Rank related past events by the computed remembering scores
• 3. Identify features (e.g., time, location) having a high correlation with remembering

Our Approach

Remembering scores: a linear combination of three features:

• 1. Cross-correlation coefficient (CCF)
• 2. Sum of squared error (SSE)
• 3. Skewness (Kurtosis)

Measuring Signals for Memory Revival

Remembering scores: a linear combination of three features:

• 1. Cross-correlation coefficient (CCF)
• 2. Sum of squared error (SSE)
• 3. Skewness (Kurtosis)

Measuring Signals for Memory Revival

Remembering scores: a linear combination of three features:

• 1. Cross-correlation coefficient (CCF)
• 2. Sum of squared error (SSE)
• 3. Skewness (Kurtosis)

Measuring Signals for Memory Revival

Remembering = α•CCF + β•SSE + γ•Kurtosis

Features for Triggered Remembering

Temporal similarity:

• Time distance between two events (in days, months or years)
• Time distance based on exponential decay functions

Location similarity:

• Map a geographic hierarchy of event locations as follows

 city -> state -> country -> neighbor countries -> continent

• Assign 4 scale values: 4 to same city, 3 to state, 2 to country,1 to continent

Impact of Events:

• Damaged area/properties/cost/fatalities
• Magnitude (for earthquake events)
• Highest winds, lowest pressure (for Atlantic hurricanes)
• N. Kanhabua and K. Nørvåg: Determining time of queries for re-ranking search results. ECDL 2010
• J. Strötgen, M. Gertz, and C. Junghans: An event-centric model for multilingual document similarity. SIGIR 2011

Experiments

Datasets:

• Page views statistics 2007-2013
• A large set of 5,500 events
• From 11 event-related categories
• α = 0.5, β = 0.4, γ = 0.1

Temporal and spatial distributions

• Strong focus on more recent events
• Better coverage with increasing popularity
• Most frequent locations depending on event types

Temporal and Spatial Distributions

Temporal and spatial distributions

• Strong focus on more recent events
• Better coverage with increasing popularity
• Most frequent locations depending on event types

Temporal and Spatial Distributions

Temporal and spatial distributions

• Strong focus on more recent events
• Better coverage with increasing popularity
• Most frequent locations depending on event types

Temporal and Spatial Distributions

Category: Atlantic Hurricane

Distributions of remembering scores

• Hurricane Sandy (Form date: October 22, 2012, Affected area: Mid-Atlantic)
• Hurricane Hanna (Form date: August 28, 2008, Affected area: US east coast)

Category: Atlantic Hurricane

Distributions of remembering scores

• Hurricane Sandy (Form date: October 22, 2012, Affected area: Mid-Atlantic)
• Hurricane Hanna (Form date: August 28, 2008, Affected area: US east coast)

Location and time have a low effect on remembering scores for this category.

Category: Atlantic Hurricane

Top-10 events triggered by the two events

• Hurricane Hanna commemorates Hurricane Gustav, the freshest hurricane

stuck at the area of Puerto Rico and East Coast

• Hurricane Sandy triggers 1991 Perfect Storm initially formed around Canada

area, which t is high impact and most destructive

Category: Atlantic Hurricane

Top-10 events triggered by the two events

• Hurricane Hanna commemorates Hurricane Gustav, the freshest hurricane

stuck at the area of Puerto Rico and East Coast

• Hurricane Sandy triggers 1991 Perfect Storm initially formed around Canada

area, which t is high impact and most destructive

Category: Aviation accidents

Mixture of impact factors, such as, time and location

• Qantas Flight 32 (crashed on 4 November 2010) triggers remembering of

(1) Qantas Flight 30 and British Airways Flight 9 (both going to Australia), and (2) Aero Caribbean Flight 883 (most recent event)

Most recent

Category: Aviation accidents

Mixture of impact factors, such as, time and location

• Qantas Flight 32 (crashed on 4 November 2010) triggers remembering of

(1) Qantas Flight 30 and British Airways Flight 9 (both going to Australia), and (2) Aero Caribbean Flight 883 (most recent event)

Same destination

Category: Aviation accidents

Mixture of impact factors, such as, time and location

• Qantas Flight 32 (crashed on 4 November 2010) triggers remembering of

(1) Qantas Flight 30 and British Airways Flight 9 (both going to Australia), and (2) Aero Caribbean Flight 883 (most recent event)

Same destination

Deadliest (two aircraft collided)

Concorde

Category: Earthquakes

A series of earthquake events at Christchurch, New Zealand

• 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and high-

impact) and two close-by events, and high-impact historical earthquakes

• 2011 Christchurch earthquake shows locality focus, i.e., people seem to be

interested in the previous events in the same region

• June 2011 Christchurch earthquake, the remembered events are dominated

by the two predecessor events

Category: Earthquakes

A series of earthquake events at Christchurch, New Zealand

• 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and high-

impact) and two close-by events, and high-impact historical earthquakes

• 2011 Christchurch earthquake shows locality focus, i.e., people seem to be

interested in the previous events in the same region

• June 2011 Christchurch earthquake, the remembered events are dominated

by the two predecessor events

Category: Earthquakes

A series of earthquake events at Christchurch, New Zealand

• 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and high-

impact) and two close-by events, and high-impact historical earthquakes

• 2011 Christchurch earthquake shows locality focus, i.e., people seem to be

interested in the previous events in the same region

• June 2011 Christchurch earthquake, the remembered events are dominated

by the two predecessor events

Category: Earthquakes

A series of earthquake events at Christchurch, New Zealand

• 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and high-

impact) and two close-by events, and high-impact historical earthquakes

• 2011 Christchurch earthquake shows locality focus, i.e., people seem to be

interested in the previous events in the same region

• June 2011 Christchurch earthquake, the remembered events are dominated

by the two predecessor events

Look beyond single events, especially, if there are several events in temporal and local proximity.

Category: Earthquakes

A series of earthquake events at Christchurch, New Zealand

• 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and high-

impact) and two close-by events, and high-impact historical earthquakes

• 2011 Christchurch earthquake shows locality focus, i.e., people seem to be

interested in the previous events in the same region

• June 2011 Christchurch earthquake, the remembered events are dominated

by the two predecessor events

Look beyond single events, especially, if there are several events in temporal and local proximity.

Category: Terrorist incidents

Interesting observation: semantic similarity between events

• June 2012 Kaduna church bombings triggers other religion terror attacks
• 2008 Mumbai attacks trigger terror attacks in business, entertainment and hotels

2nd 5th 24th

Category: Terrorist incidents

Interesting observation: semantic similarity between events

• June 2012 Kaduna church bombings triggers other religion terror attacks
• 2008 Mumbai attacks trigger terror attacks in business, entertainment and hotels

2nd 7th 15th

Conclusions

We identified some first pattern for event memory triggering for diverse event types including natural and manmade disasters as well as accidents and terrorism. Our analysis confirmed the influence of closeness in time and location, but the semantic similarity of events also influences which event memories are triggered by an event. In our future work, we plan to deepen our systematic analysis of factors for revisiting past events and of the combination of those factors. We also plan to investigate external factors such as media coverage linking new events to past events or reflection of such relationships in

• ther types of social media.

What do you remember?

Thanks for your attention!